IEC 60118-15:20 12规定了一种设计用于表示正常语音的测试信号，即国际语音测试信号（ISTS），以及测量空气传导助听器中信号处理特性的程序和要求。测量值用于导出估计的插入增益(EIG)。为了表征用于生产、供应和交付的助听器，还规定了在IEC 60318-5中定义的2 cm3耦合器上导出耦合器增益的程序和要求。本标准的目的是确保遵循所述程序并使用符合这些要求的设备在助听器上进行的相同测量给出基本相同的结果。考虑助听器与个体耳朵的声学耦合以及末端的个体解剖变化的声学影响的测量方法-用户对助听器声学性能的测量（称为真耳测量）超出了本特定标准的范围。

IEC 60118-15:2012 specifies a test signal designed to represent normal speech, the International Speech Test Signal (ISTS), together with the procedures and the requirements for measuring the characteristics of signal processing in air-conduction hearing aids. The measurements are used to derive the estimated insertion gain (EIG). For the purposes of characterizing a hearing aid for production, supply and delivery, the procedures and requirements to derive the coupler gain on a 2 cm³ coupler as defined in IEC 60318-5 are also specified. The purpose of this standard is to ensure that the same measurements made on a hearing aid following the procedures described, and using equipment complying with these requirements, give substantially the same results. Measurement methods that take into account the acoustic coupling of a hearing aid to the individual ear and the acoustic influence of the individual anatomical variations of an end-user on the acoustical performance of the hearing aid, known as real-ear measurements, are outside the scope of this particular standard.